Mirena Question

I'm not sure if this is the correct board so I'm also posting this on the TTC board but I thought some ladies here might have some experience with this. I had the mirena placed at my 6 week PP check up, I'm still BF, and my daughter will be 20 months on Monday but I still haven't got AF back yet. Not that I'm complaining. For those of you who have had an IUD removed, how long after did you get AF back? My doc said that some women stop AF all together on mirena so that's nice, but I want to make sure that everything still works (if you know what I mean) when it does come time to TTC.